Feat: Support macOS and Windows, migrate JavaScript to TypeScript (#32)

- Support macOS and Windows (Close #24 )
- Refactoring
  - Error handling
  - TypeScript
- Prettier (Close #29 )
- GHA: Add upload-artifact step for test coverage
- deps: Install husky

src/get-latest-version.ts

@@ -0,0 +1,19 @@
+const XMLHttpRequest = require('xmlhttprequest').XMLHttpRequest;
+
+export default function getLatestVersion(): Promise<string> {
+  return new Promise((resolve, reject) => {
+    const xhr = new XMLHttpRequest();
+    const url: string = 'https://formulae.brew.sh/api/formula/hugo.json';
+    xhr.open('GET', url);
+    xhr.send();
+    xhr.onreadystatechange = function() {
+      if (xhr.readyState === 4 && xhr.status === 200) {
+        const result = JSON.parse(xhr.responseText);
+        const latestVersion: string = result.versions.stable;
+        resolve(latestVersion);
+      } else if (xhr.readyState === 4 && xhr.status !== 200) {
+        reject(`ERROR: got status ${xhr.status} of ${url}`);
+      }
+    };
+  });
+}